[PATCH v2 2/2] platform/chrome: Update cros_ec sysfs attributes on sensors discovery

[Gwendal Grignou <gwendal@chromium.org>]

When cros_ec_sysfs probe is called before cros_ec_sensorhub probe
routine, the |kb_wake_angle| attribute will not be displayed, even if
there are two accelerometers in the chromebook.

Call sysfs_update_groups() when accelerometers are enumerated if the
cros_ec sysfs attributes groups have already been created.

Fixes: d60ac88a62df ("mfd / platform / iio: cros_ec: Register sensor through sensorhub")
Cc: stable@vger.kernel.org
Signed-off-by: Gwendal Grignou <gwendal@google.com>
---
 Changes in v2:
 Rebase after .dev_groups is used.

 drivers/platform/chrome/cros_ec_sensorhub.c |  6 +++++-
 drivers/platform/chrome/cros_ec_sysfs.c     | 10 ++++++++++
 include/linux/platform_data/cros_ec_proto.h |  2 ++
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/chrome/cros_ec_sensorhub.c b/drivers/platform/chrome/cros_ec_sensorhub.c
index 9c4af76a9956e..c69fec935fb50 100644
--- a/drivers/platform/chrome/cros_ec_sensorhub.c
+++ b/drivers/platform/chrome/cros_ec_sensorhub.c
@@ -106,8 +106,11 @@ static int cros_ec_sensorhub_register(struct device *dev,
 		sensor_type[sensorhub->resp->info.type]++;
 	}
 
-	if (sensor_type[MOTIONSENSE_TYPE_ACCEL] >= 2)
+	if (sensor_type[MOTIONSENSE_TYPE_ACCEL] >= 2) {
 		ec->has_kb_wake_angle = true;
+		if (ec->groups && sysfs_update_groups(&ec->class_dev.kobj, ec->groups))
+			dev_warn(dev, "Unable to update cros-ec-sysfs");
+	}
 
 	if (cros_ec_check_features(ec,
 				   EC_FEATURE_REFINED_TABLET_MODE_HYSTERESIS)) {
diff --git a/drivers/platform/chrome/cros_ec_sysfs.c b/drivers/platform/chrome/cros_ec_sysfs.c
index 114b9dbe981e7..b363f70270a38 100644
--- a/drivers/platform/chrome/cros_ec_sysfs.c
+++ b/drivers/platform/chrome/cros_ec_sysfs.c
@@ -340,11 +340,21 @@ static const struct attribute_group *cros_ec_attr_groups[] = {
 	NULL,
 };
 
+static int cros_ec_sysfs_probe(struct platform_device *pd)
+{
+	struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
+
+	ec_dev->groups = cros_ec_attr_groups;
+
+	return 0;
+}
+
 static struct platform_driver cros_ec_sysfs_driver = {
 	.driver = {
 		.name = DRV_NAME,
 		.dev_groups = cros_ec_attr_groups,
 	},
+	.probe = cros_ec_sysfs_probe,
 };
 
 module_platform_driver(cros_ec_sysfs_driver);
diff --git a/include/linux/platform_data/cros_ec_proto.h b/include/linux/platform_data/cros_ec_proto.h
index 02599687770c5..de940112f53ae 100644
--- a/include/linux/platform_data/cros_ec_proto.h
+++ b/include/linux/platform_data/cros_ec_proto.h
@@ -191,6 +191,7 @@ struct cros_ec_platform {
 /**
  * struct cros_ec_dev - ChromeOS EC device entry point.
  * @class_dev: Device structure used in sysfs.
+ * @groups: sysfs attributes groups for this EC.
  * @ec_dev: cros_ec_device structure to talk to the physical device.
  * @dev: Pointer to the platform device.
  * @debug_info: cros_ec_debugfs structure for debugging information.
@@ -200,6 +201,7 @@ struct cros_ec_platform {
  */
 struct cros_ec_dev {
 	struct device class_dev;
+	const struct attribute_group **groups;
 	struct cros_ec_device *ec_dev;
 	struct device *dev;
 	struct cros_ec_debugfs *debug_info;
-- 
2.31.0.208.g409f899ff0-goog